Can stress cause fever? The perplexing science of your internal state

Americans are incredibly stressed. One-third of all Americans have said their mental health has suffered as a direct result of the Covid-19 pandemic. According to the 2020 Stress in America report, the average stress level reported for adults is a 5.9. Last year it was 4.9. Many people are having to navigate a loss of income and a loss of social ties, all while worrying about not becoming sick with coronavirus.

Apart from polls, spiking Google searches can also serve as a looking glass into a nation’s psyche. One, in particular, is especially ripe for this moment: “Can stress cause fever?” Over the last 12 months, Google interest in this search term has grown by 160 percent. Interest peaked in April, before falling in June. Now, it is on the rise again.

The answer isn’t exactly complicated, but how you apply it to your life can be. Stress can cause a rise in body temperature. But a rising body temperature does not mean that you have the level of fever that’s associated with Covid-19. It’s rude that coronavirus stress can raise your temperature, in turn making you more worried about coronavirus, but there’s the rub.

Body temperature, in general, is not a stagnant thing. It varies over the course of the day, with later hours associated with higher temperatures, and is influenced by one’s metabolic rate. Despite the myth of 98.6 degrees, there’s no “normal” body temperature — and if there was, recent research says it actually would be closer to 97.9 degrees. Doctors typically view a body temperature between 97 to 99 as healthy: The CDC typically only classifies temperatures over 100 degrees as a fever.

Feeling mentally stressed is a physiological change that can cause a rise in body temperature, known as psychological stress-induced hyperthermia. It’s viewed as an autonomic stress response and is observed in many mammal species. It’s also considered to be evolutionarily beneficial — a warming up of the muscles and the central nervous system that allows animals, including humans, to survive “fight or flight” situations. In rats, simply being moved into a new cage can raise their body temperature by more than 1 degree Celsius.

Long-lasting psychological stress can actually cause chronic hyperthermia, which is also known as “psychogenic fever.” The condition is understudied, and likely underrecognized, but it is manifested as high body temperature. According to a 2015 review in the journal Temperature, some patients develop a core body temperature up to 105 degrees after being exposed to an extremely emotional event, while others show a persistent fever of 100 degrees when experiencing chronic stress.

It’s possible that one’s temperature is a result of stress, rather than Covid-19. What’s essential is to take note of what the temperature actually is, and how long it has persisted. A slight rise most likely doesn’t mean that you’re becoming ill. If you want to monitor your health, the CDC recommends:

• Taking your temperature two times a day for 14 days, making sure you record it.
• Before you take your temperature you should wait 30 minutes after eating, drinking, or exercising, and 6 hours after taking medicine that can lower a temperature.
• If your temperature is consistently above 100.4, it’s time to call your doctor.

It’s important to remember to be mindful of the other symptoms associated with Covid-19, and remember that it can between 2 and 14 days after exposure to the virus for symptoms to appear. These include, but are not limited to: cough, shortness of breath, chills, repeated shaking with chills, muscle pain, headache, sore throat, diarrhea, and a new loss of taste or smell.

If it’s stress that’s the root of your fever, there are steps you can take to manage it. These include exercising, proactive coping, box-breathing, and giving your pet a hug.